#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int i, arr[10],sum=0;
	double avg = 0;
	for (i = 0; i < 10; ++i)
	{
		scanf("%d", &arr[i]);
		sum += arr[i];
	}
	avg = sum / 10.0;
	printf("%.2lf\n", avg);
	return 0;
}